From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-11.4 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_IN_DEF_DKIM_WL autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6B4C9C388F7 for ; Tue, 10 Nov 2020 19:00:10 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id F337D20780 for ; Tue, 10 Nov 2020 19:00:09 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="UAf9RqBB" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731133AbgKJTAJ (ORCPT ); Tue, 10 Nov 2020 14:00:09 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46538 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730382AbgKJTAI (ORCPT ); Tue, 10 Nov 2020 14:00:08 -0500 Received: from mail-vs1-xe42.google.com (mail-vs1-xe42.google.com [IPv6:2607:f8b0:4864:20::e42]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4C537C0613D4 for ; Tue, 10 Nov 2020 11:00:08 -0800 (PST) Received: by mail-vs1-xe42.google.com with SMTP id f7so7689976vsh.10 for ; Tue, 10 Nov 2020 11:00:08 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=HQMWJ4qrTrrDaVP4fR8AYbnLL+HhbqUgRWbw+YSQ1PU=; b=UAf9RqBB0qr82AsqOtHV2sesZ3cFzDvVPrFOFo9wUuuHJXryVnBngDsIrGvKaE6X19 0SqjoI+qK8F47wcovy/kBeCPJ4lIKLolgnCYTTAinI6LM/5ys2dh6HlhdigZSrVkC/rn ShAlUOfI+vdr9rptwftYPxBYiTijHNtuYVGc3mYzd/3mrO/nNNPGBPmWtes0yy3EJX3R sHQB4adTCc34sogEGEr66NVJxa45ZnJ2DpryOQ0DhgNiqen71LLeDBvfUdLT3d4QP0EK CCvE4ObR4otzBFPgR6yeCqhZTLFHqyDs2Tr4Y5R18i3xk72lbdkEjxSGufRjUQd0yCL8 Ojbw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=HQMWJ4qrTrrDaVP4fR8AYbnLL+HhbqUgRWbw+YSQ1PU=; b=F0lo5j21UWupSRc/KugAKs9QXokzP/FMYzBqUso9IFGWAFtxfpP9hJ9TDeTclpELmk 6HK1tw945TB3BWPbUtaIOUdG1cVdbjohdS/Qf9m3G2sOxXKz6DMujHc2RwCzh4uPN/pj rKyQKHj7tlOKutAhXmG+OMxucbqGGUqIpzC8LQZWEEU/SkJIURSlzj9fSuoxWP3dE+NM fihTFNHYlw/MQGbJvmuaaCEA68ckpPI+JrPEzqrcO0/nxh0wOcNGc9fV55IB0p9GzGUP 6cRRqg2AqzfxPG3i/JQPMRCQzcsv0WFuV4me8HdlBpxHo6CzPkPfXeoroE5uVJXuvzK+ Liag== X-Gm-Message-State: AOAM532mj4SLOO2pKZWrbOAOogoU1kkusyPi4A8ac5efQx0G+I9wvGQc Km9nKMC2pwe5ZBo9Bo4yFGiubIgtfucbMTpQQakf3w== X-Google-Smtp-Source: ABdhPJw/xQbpb4nm+Nf8IkeXZp9mvPOXpptK1b90vfr96ZwBHQ1ynLFLCpnmKb8sXq4PoJSCYGgPJD2CoGITJLPmHok= X-Received: by 2002:a67:ee93:: with SMTP id n19mr12787183vsp.36.1605034807022; Tue, 10 Nov 2020 11:00:07 -0800 (PST) MIME-Version: 1.0 References: <20201015102216.GB2611@hirez.programming.kicks-ass.net> <20201015203942.f3kwcohcwwa6lagd@treble> <20201020185217.ilg6w5l7ujau2246@treble> <20201021085606.GZ2628@hirez.programming.kicks-ass.net> <20201023173617.GA3021099@google.com> <20201110022924.tekltjo25wtrao7z@treble> <20201110174606.mp5m33lgqksks4mt@treble> In-Reply-To: <20201110174606.mp5m33lgqksks4mt@treble> From: Sami Tolvanen Date: Tue, 10 Nov 2020 10:59:55 -0800 Message-ID: Subject: Re: [PATCH v6 22/25] x86/asm: annotate indirect jumps To: Josh Poimboeuf Cc: Peter Zijlstra , Jann Horn , "the arch/x86 maintainers" , Masahiro Yamada , Steven Rostedt , Will Deacon , Greg Kroah-Hartman , "Paul E. McKenney" , Kees Cook , Nick Desaulniers , clang-built-linux , Kernel Hardening , linux-arch , Linux ARM , linux-kbuild , kernel list , linux-pci@vger.kernel.org Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kbuild@vger.kernel.org On Tue, Nov 10, 2020 at 9:46 AM Josh Poimboeuf wrote: > > On Mon, Nov 09, 2020 at 08:29:24PM -0600, Josh Poimboeuf wrote: > > On Mon, Nov 09, 2020 at 03:11:41PM -0800, Sami Tolvanen wrote: > > > CONFIG_XEN > > > > > > __switch_to_asm()+0x0: undefined stack state > > > xen_hypercall_set_trap_table()+0x0: <=== (sym) > > With your branch + GCC 9 I can recreate all the warnings except this > one. In a gcc build this warning is replaced with a different one: vmlinux.o: warning: objtool: __startup_secondary_64()+0x7: return with modified stack frame This just seems to depend on which function is placed right after the code in xen-head.S. With gcc, the disassembly looks like this: 0000000000000000 : 0: e8 00 00 00 00 callq 5 1: R_X86_64_PLT32 cpu_bringup_and_idle-0x4 5: e9 f6 0f 00 00 jmpq 1000 ... 0000000000001000 : ... ... 0000000000002000 <__startup_secondary_64>: With Clang+LTO, we end up with __switch_to_asm here instead of __startup_secondary_64. > Will do some digging on the others... Thanks! Sami